Wind farm visual impact assessment – part 2

Warning

The viewshed maps on this page are very detailed and may take quite a while to display in many web browsers, and may not render at all on small devices such as smartphones or tablets. They are provided purely for development purposes, and final versions will be optimised for faster display.

Calculating compound viewsheds

The map below shows the independent viewsheds (with Earth curvature and atmospheric refraction corrections) for three of the proposed Palings Yard wind turbines at a tip elevation of 170.5m at the indicated positions. By independent we mean that the viewshed for each turbine is separate and not combined with the others, although they obviously overlay each other by a large degree.

Displaying number of turbines visible

The next step is to calculate how many turbines are visible. Here the map is shaded according to how many towers are visible from each point on the map, from zero (transparent shading) to three (since there are only three hypothetical towers in this example, for the sake of simplicity). This is a compound viewshed – that is, it is the union of each of the three independent viewshed for the three hypothetical turbines in this example.

Displaying number of turbines visible as separate layers

Here is the same map but with separate layers for each number of visible turbines, to allow easier examination of the data.

Next steps

In the next in this series of blog posts we will extend the calculation done here to include all of the 47 wind turbines proposed for the palings Yard wind farm.